GT/ All-in-one solar-powered tower makes carbon-neutral jet fuel
Energy & green technology biweekly vol.29, 15th July — 29th July
TL;DR
- Researchers have designed a fuel production system that uses water, carbon dioxide (CO2), and sunlight to produce aviation fuel. They have implemented the system in the field, and the design could help the aviation industry become carbon neutral.
- Passive day cooling is a promising technology for the sustainable reduction of energy consumption. Researchers have now created a test system with which the materials used for passive cooling can be reliably characterized and compared — regardless of weather conditions and environmental conditions.
- In an important step toward bringing transparent solar cells to home windows, researchers have developed a way to manufacture their highly efficient and semitransparent solar cells.
- Researchers have come up with a novel way to study the thermodynamic properties of molten salts, which are used in many nuclear and solar energy applications.
- As more and more wind turbines are installed in the course of the energy transition and distance regulations to human settlements are tightened, suitable locations are becoming increasingly difficult to find. As a result, wind turbines are increasingly being erected in forests — to the detriment of forest specialists among bats.
- A groundbreaking new study comprehensively accounts for the hydrological impact of lithium mining. Since lithium is the key component of the lithium-ion batteries that are crucial for the transition away from fossil fuels and towards green energy, it is critical to fully understand how to responsibly obtain the precious element.
- Air pollution, climate change, and public health are closely linked, as a new study shows. The report details on a town-by-town basis the deaths and illnesses caused by air pollution in Massachusetts, and also outlines steps to curb fine particulate pollutants. Nationally, the study offers a model that can be followed by other states using public data and open-source software, according to a public health expert and practitioner.
- A study of 29 European lakes has found that some naturally-occurring lake bacteria grow faster and more efficiently on the remains of plastic bags than on natural matter like leaves and twigs. The bacteria break down the carbon compounds in plastic to use as food for their growth.
- To save the world’s fish stocks and oceans, scientists are racing to find better and sustainable ways to make healthy nutritional products such as Omega-3 fatty acids, biodiesel, aquaculture and livestock food from fast-growing microalgae. New research has discovered a simple, low-cost and effective way to extract high-value bioactives from single-cell algae oil — using waste sulfur from industries such as petrochemical production.
- New research offers a second life for CDs: Turn them into flexible biosensors that are inexpensive and easy to manufacture.
- And more!
Green Technology Market
Green technology is an applicable combination of advanced tools and solutions to conserve natural resources and environment, minimize or mitigate negative impacts from human activities on the environment, and ensure sustainability development. Green technology is also referred to as clean technology or environmental technology which includes technologies, such as IoT, AI, analytics, blockchain, digital twin, security, and cloud, which collect, integrate, and analyze data from various real-time data sources, such as sensors, cameras, and Global Positioning System (GPS).
Green technology, also known as sustainable technology, protects the environment by using various forms of sustainable energy. Some of the best examples of green technologies include solar panels, LED lighting, wind energy, electric vehicles, vertical farming, and composting.
The global Green Technology and Sustainability market size to grow from USD 11.2 billion in 2020 to USD 36.6 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 26.6% during the forecast period. The growing consumer and industrial interest for the use of clean energy resources to conserve environment and increasing use of Radio Frequency Identification sensors across industries are driving the adoption of green technology and sustainability solutions and services in the market.
The blockchain segment is estimated to grow at the highest CAGR: Energy-intensive cryptocurrency mining has caused a spike in carbon emission, and hence blockchain is capable of driving innovation in the field of green technology.
Latest Research
A solar tower fuel plant for the thermochemical production of kerosene from H2O and CO2
by Adriano Patané, Philipp Haueter, Manuel Romero, José González-Aguilar, Dick Lieftink, Ellart de Wit, Stefan Brendelberger, Andreas Sizmann, Aldo Steinfeld in Joule
Researchers have designed a fuel production system that uses water, carbon dioxide (CO2), and sunlight to produce aviation fuel. They have implemented the system in the field, and the design could help the aviation industry become carbon neutral.
“We are the first to demonstrate the entire thermochemical process chain from water and CO2 to kerosene in a fully-integrated solar tower system,” says Aldo Steinfeld, a professor from ETH Zurich and the corresponding author of the paper. Previous attempts to produce aviation fuels through the use of solar energy have mostly been performed in the laboratory.
The aviation sector is responsible for about 5% of global anthropogenic emissions causing climate change. It relies heavily on kerosene, or jet fuel, which is a liquid hydrocarbon fuel typically derived from crude oil. Currently, no clean alternative is available to power long-haul commercial flights at the global scale.
“With our solar technology, we have shown that we can produce synthetic kerosene from water and CO2 instead of deriving it from fossil fuels. The amount of CO2 emitted during kerosene combustion in a jet engine equals that consumed during its production in the solar plant,” Steinfeld says. “That makes the fuel carbon neutral, especially if we use CO2 captured directly from the air as an ingredient, hopefully in the not-too-distant future.”
As a part of the European Union’s SUN-to-LIQUID project, Steinfeld and his colleagues have developed a system that uses solar energy to produce drop-in fuels, which are synthetic alternatives to fossil-derived fuels such as kerosene and diesel. The solar-made kerosene is fully compatible with the existing aviation infrastructure for fuel storage, distribution, and end use in jet engines, Steinfeld says. It can also be blended with fossil-derived kerosene, he adds.
In 2017, the team started scaling up the design and built a solar fuel-production plant at IMDEA Energy Institute in Spain. The plant consists of 169 sun-tracking reflective panels that redirect and concentrate solar radiation into a solar reactor mounted on top of a tower. The concentrated solar energy then drives oxidation-reduction (redox) reaction cycles in the solar reactor, which contains a porous structure made of ceria. The ceria -which is not consumed but can be used over and over -converts water and CO2 injected into the reactor into syngas, a tailored mixture of hydrogen and carbon monoxide. Subsequently, syngas is sent into a gas-to-liquid converter, where it is finally processed into liquid hydrocarbon fuels that include kerosene and diesel.
“This solar tower fuel plant was operated with a setup relevant to industrial implementation, setting a technological milestone towards the production of sustainable aviation fuels,” Steinfeld says.
During a nine-day run of the plant reported in the paper, the solar reactor’s energy efficiency — the portion of solar energy input that is converted into the energy content of the syngas produced — was around 4%. Steinfeld says his team is working intensively on improving the design to increase the efficiency to values over 15%. For example, they are exploring ways to optimize the ceria structure for absorbing solar radiation and developing methods to recover the heat released during the redox cycles.
A tailored indoor setup for reproducible passive daytime cooling characterization
by Qimeng Song, Thomas Tran, Kai Herrmann, Tobias Lauster, Maximilian Breitenbach, Markus Retsch in Cell Reports Physical Science
Passive day cooling is a promising technology for the sustainable reduction of energy consumption. It avoids the heating up of buildings by solar radiation and dissipates accumulated heat without external energy consumption. Researchers at the University of Bayreuth have now created a test system with which the materials used for passive cooling can be reliably characterised and compared — regardless of weather conditions and environmental conditions. The measurement setup is the first step towards a standardised, globally applicable test system for comparing high-performance cooling materials.
“Increasing fossil energy consumption worldwide is still contributing to global warming and is a major cause of the heating up of our cities. Cooling buildings during the day using passive cooling materials has great potential to establish itself as an effective tool for energy conservation. Many technologically interesting materials and classes of material have consequently been developed for the dissipation of heat, but it is still a challenge to precisely determine and compare their performance. The laboratory set-up we have designed helps to overcome this difficulty. It is a test system that makes important contributions to the characterisation of previously existing cooling materials and the design of new ones, regardless of the weather,” says Prof. Dr. Markus Retsch, project leader of the study and Chair of Physical Chemistry I at the University of Bayreuth.
The laboratory-based test system mimics the most important factors that influence passive cooling performance. Essential components are therefore a simulator of sunlight, an aluminium dome cooled with liquid nitrogen that absorbs thermal radiation, a changeable filter that only allows light rays of certain wavelengths to pass through, and a heatable gas flow that can be used to set a specific ambient temperature. This allows the intensity of solar radiation, the temperatures acting on the cooling materials, and other environmental influences to be simulated on a miniature scale. Outdoors, these factors change quickly and cannot be controlled, but in the new measurement setup from Bayreuth, they can be set with great specificity. As a result, the test results are reproducible at any time, regardless of time, place, or weather. This is the only way to characterise the properties and behaviour of cooling materials with high precision and to compare them under identical conditions. The measurement setup is robust, cost-effective, and also has the advantage of being replicable without great technical effort.
The Bayreuth scientists have demonstrated the high performance and reliability of the test system on three different materials: a silver mirror (Ag), a film of polydimethylsiloxane (PDMS) applied to silver, and a graphite-coated silicon wafer. In doing so, they not only tested the heating and cooling of the materials, but also determined their cooling performance.
“Our measurement setup is the first step towards standardised performance comparisons between cooling materials that have been developed around the world under very different climatic and weather conditions. Such a test system is an important prerequisite for passive cooling to become a globally applied technology for significantly reducing energy consumption,” says Dr. Qimeng Song, first author of the study and postdoc at the research group led by Prof. Dr. Markus Retsch.
Multilevel peel-off patterning of a prototype semitransparent organic photovoltaic module
by Xinjing Huang, Dejiu Fan, Yongxi Li, Stephen R. Forrest in Joule
In an important step toward bringing transparent solar cells to home windows, researchers at the University of Michigan have developed a way to manufacture their highly efficient and semitransparent solar cells.
“In principle, we can now scale semitransparent organic solar cells to two meters by two meters, which brings our windows much closer to reality,” said Stephen Forrest, the Peter A. Franken Distinguished University Professor of Electrical Engineering and corresponding author of a study.
Traditional silicon-based solar cells are completely opaque, which works for solar farms and roofs but would defeat the purpose of windows. However, organic solar cells, in which the light absorber is a kind of plastic, can be transparent. Organic solar cells have lagged behind their silicon-based cousins for energy-producing purposes due to engineering challenges such as low efficiency and short lifespans, but recent work out of Forrest’s lab has achieved record efficiencies of 10% and estimated lifetimes of up to 30 years.
So the team has turned its attention to making transparent solar cells manufacturable. A significant challenge is creating the micron-scale electrical connections between individual cells that comprise the solar module. Conventional methods that use lasers to pattern the cells can easily damage the organic light absorbers. Instead, the team developed a multistep peel-off patterning method that achieved micron-scale resolution. They deposited thin films of plastic and patterned them into extremely thin strips. Then, they set down the organic and metal layers. Next, they peeled off the strips, creating very fine electrical interconnections between the cells.
The group connected eight semitransparent solar cells, each 4 cm x 0.4 cm and separated by 200µm-wide interconnections, to create a single 13 cm2 module. The power conversion efficiency of 7.3% was approximately 10% less than for the individual solar cells in the module. This small efficiency loss does not increase with the size of the module; hence, similar efficiencies are expected for meter-scale panels as well. With a transparency nearing 50% and a greenish tint, the cells are suitable for use in commercial windows. Higher transparencies that are likely preferred for the residential market are easily achieved by this same technology.
“It is now time to get industry involved to turn this technology into affordable applications,” said Xinjing Huang, U-M doctoral student in applied physics and first author on the published research.
Eventually, the flexible solar cell panel will be sandwiched between two window panes. The goal for these energy-generating window films is to be about 50% transparent with 10%-15% efficiency. Forrest believes this can be achieved within a couple years.
“The research we are doing is derisking the technology so that manufacturers can make the investments needed to enter large scale production,” Forrest said.
The technique can also be generalized to other organic electronic devices, he says. And in fact, his group is already applying it to OLEDs for white lighting.
A replicable strategy for mapping air pollution’s community-level health impacts and catalyzing prevention
by Philip J. Landrigan, Samantha Fisher, Maureen E. Kenny, Brittney Gedeon, Luke Bryan, Jenna Mu, David Bellinger in Environmental Health
Air pollution remains a silent killer in Massachusetts, responsible for an estimated 2,780 deaths a year and for measurable cognitive loss in Bay State children exposed to fine particulate pollutants in the air they breathe, according to a new study by researchers at Boston College’s Global Observatory on Planetary Health.
The study was supported by the Barr Foundation and is the first to examine far-reaching public health consequences of air pollution in the state on a town-by-town basis. The study found air-pollution-related disease, death and IQ loss occur in every city and town regardless of demographics or income level. Highest rates were in the most economically disadvantaged and socially underserved cities and towns. The Boston College team estimates the cumulative impact on childhood cognitive development in Massachusetts in 2019 was a loss of almost 2 million Performance IQ points, or more than 2 IQ points for the average child, according to the report. IQ loss impairs children’s school performance and reduces graduation rates, the team noted.
“We are talking about the impacts of air pollution at a very local level in Massachusetts — not just statewide,” said lead author Boston College Professor of Biology Philip J. Landrigan, MD, director of the Observatory. “This report gives the people in every city and town the opportunity to see for themselves the quality of the air they and their families are breathing and the dangerous health implications for both adults and children as a consequence of air pollution.”
“All of these health effects occurred at pollution levels below current EPA standards,” Landrigan noted.
The average level of fine particulate pollution across Massachusetts in 2019 was 6.3 micrograms per cubic meter, and levels ranged from a low of 2.77 micrograms per cubic meter in Worcester County to a high of 8.26 in Suffolk County. The U.S. Environmental Protection Agency standard is 12 micrograms per cubic meter, and the World Health Organization’s recommended guideline is 5.
“Clearly, current EPA air pollution standards are not adequately protecting public health,” Landrigan said.
Town-by-town air pollution information is not typically available, given there are not enough air quality monitoring stations in the state. The team determined levels for all cities and towns using available data and computer modeling. While Massachusetts meets federal clean air guidelines and air pollution in the U.S. has declined 70 percent since the passage of the Clean Air Act in the 1970s — when Landrigan and other scientists successfully pushed for the removal of lead from gasoline — unclean air at current levels still poses health hazards to both healthy individuals and those with other ailments or illnesses.
“We do not have the level of air pollution you see in China or India and because it is mostly invisible today people tend to forget about air pollution and we get complacent,” Landrigan said. “We hope to break through this complacency and increase awareness. Air pollution is killing 2,780 people in Massachusetts each year, nearly 5 percent of all deaths in the state, and that is a big deal. Air pollution is something we can fix. We know the steps that need to be taken to reduce fatalities and the impact on our children and grandchildren. Now citizens in every city and town across the Commonwealth need to urge our elected officials to take those necessary steps.”
Additional findings include:
- Of the 2,780 deaths attributable to air pollution in Massachusetts in 2019, at least 2,185 were due to lung cancer 1,677 to heart disease, 343 to chronic lung disease, and 200 to stroke.
- Air pollution was responsible for 15,386 cases of pediatric asthma and an estimated 308 low-birthweight babies (5.5 lbs. or less).
More than 95 percent of air pollution in Massachusetts results from the combustion of fossil fuels. Cars, trucks, buses, planes, trains and ships produced two-thirds of pollutant emissions-655,000 tons — in 2017, the most recent year for which data were available. Power plants, industrial facilities, and home heating and cooking produced 283,000 tons. In all, these sources emitted 938,000 tons of pollutants. Fossil fuel combustion is also the major source of the carbon dioxide and other greenhouse gases that drive global climate change, which the researchers said should further incentivize Massachusetts to reduce air pollution and greenhouse gas emissions by transitioning to cleaner fuels.
“Air pollution harms our environment and young people, and these burdens disproportionately impact environmental justice communities,” said Kathryn Wright, the Barr Foundation’s Senior Program Officer for Clean Energy. “Meaningful action on climate change requires us to swiftly address air pollution from transportation and our energy system and its many harmful effects.”
Fine particulate air pollution is linked to multiple non-communicable diseases in adults, including cardiovascular disease, stroke, lung cancer and diabetes. Among infants and children air pollution increases risk for premature birth, low birthweight, stillbirth, impaired lung development, and asthma.
“All of these adverse health effects occur at fine particulate matter pollution levels below the U.S. Environmental Protection Agency’s current annual standard of 12 micrograms per cubic meter,” said Landrigan. “So even for a state like Massachusetts, which registered below that standard, air pollution is a formidable public health threat that needs urgently to be addressed.”
Deep neural network based quantum simulations and quasichemical theory for accurate modeling of molten salt thermodynamics
by Yu Shi, Stephen T. Lam, Thomas L. Beck in Chemical Science
A chemist at the University of Cincinnati has come up with a novel way to study the thermodynamic properties of molten salts, which are used in many nuclear and solar energy applications.
UC College of Arts and Sciences research associate and computational chemist Yu Shi and his collaborators developed a new simulation method to calculate free energy using deep learning artificial intelligence.
Molten salt is salt heated to high temperatures where it becomes liquid. UC researchers studied sodium chloride, commonly known as table salt. Shi said molten salt has properties that make it a valuable medium for cooling systems in nuclear power plants. In solar towers, they can be used to transfer heat or store energy. Paradoxically, while salt is an insulator, molten salt conducts electricity.
“Molten salts are stable at high temperatures and can hold a lot of energy in a liquid state,” Shi said. “They have good thermodynamic properties. That makes them a good energy storage material for concentrated solar power plants. And they can be used as a coolant in nuclear reactors.”
The study could help researchers examine the corrosion that these salts can cause in metal containers like those found in the next generation of nuclear reactors. The study provides a reliable approach to study the conversion of dissolved gas to vapor in molten salts, helping engineers understand the effect of different impurities and solutes (the substance dissolved in a solution) on corrosion. Shi said it also will help researchers study the release of potentially toxic gas into the atmosphere, which will be extremely useful for fourth-generation molten salt nuclear reactors.
“We used our quasi-chemical theory and our deep neural network, which we trained using data generated by quantum simulations, to model the solvation thermodynamics of molten salt with chemical accuracy,” Shi said.
Study co-author Thomas Beck is former head of UC’s Department of Chemistry and now works as section head of science engagement for the Oak Ridge National Laboratory in Tennessee. Beck said molten salts do not expand when heated, unlike water which can create extreme pressure at high temperatures.
“The pressure inside a nuclear reactor goes up a lot. That’s the difficulty of reactor design — it leads to more risks and higher costs,” he said.
Researchers turned to UC’s Advanced Research Computing Center and the Ohio Supercomputer Center to run the simulations.
“At Oak Ridge, we have the world’s fastest supercomputer, so our experiment would take less time here,” Beck said. “But on typical supercomputers, it can take weeks or months to run these quantum simulations.”
The research team also included Stephen Lam at the University of Massachusetts Lowell.
“It’s important to have accurate models of these salts. We were the first group to calculate free energy of sodium chloride at high temperature in liquid and compare it to previous experiments,” Beck said. “So we proved it’s a useful technique.”
In 2020, Shi and Beck established a free-energy scale for single-ion hydration using quasi-chemical theory and quantum mechanical simulations of the sodium ion in water in a study published in the journal PNAS. It was the first solvation free-energy calculation for the charged solute using quantum mechanics, Shi said. Beck said molten salts will be important for developing new sources of energy — even perhaps one day fusion energy.
“They’re proposing using molten salts as a coating coolant for the high-temperature reactor,” he said. “But fusion is farther down the road.”
Activity of forest specialist bats decreases towards wind turbines at forest sites
by Julia S. Ellerbrok, Anna Delius, Franziska Peter, Nina Farwig, Christian C. Voigt in Journal of Applied Ecology
As more and more wind turbines (WTs) are installed in the course of the energy transition and distance regulations to human settlements are tightened, suitable locations are becoming increasingly difficult to find. As a result, wind turbines are increasingly being erected in forests — to the detriment of forest specialists among bats. In a new study, a team of scientists led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) demonstrated that forest specialists among bats, which forage below the treetop and thus do not have an increased risk of colliding with turbines, avoid the vicinity of wind turbines. Forest sites should therefore either not be used at all for wind turbines, or only in exceptional cases with mandated compensatory measures to protect forest bats, the team concludes.
More and more wind turbines are being installed worldwide in order to meet the goals of national climate strategies. In Germany, around 30,000 onshore wind turbines are currently in operation. However, the open areas on which wind turbines are tolerated near towns and villages are limited. For this reason wind turbines are increasingly being erected in forests.
“Forests are sensitive ecosystems and valuable habitats for many rare and protected bat species,” says Dr Christian Voigt, Head of the Department of Evolutionary Ecology at Leibniz-IZW. “Wind turbines in forests can cause problems for bats in several ways. Bats that hunt for insects above the treetops can be killed directly at the turbines if they collide with the rotor blades or do not survive the intense air pressure differences near the blades. Bats that hunt in the vegetation below the treetops lose part of their habitat because of the creation of clearings.” Their habitat could also deteriorate in the wider vicinity of wind turbines and clearings if they are disturbed by the operation of the turbines.
Together with colleagues from Phillips-Universität Marburg and Kiel University, Voigt and his student primarily looked at those bats that forage below the treetop in the shelter of the vegetation. To do this, they monitored the activity of bats using ultrasound detectors at different distances from the wind turbines at 24 forest sites in Hessen. The scientists classified the recorded calls into three groups of bats. Firstly, those that forage in open areas (e.g. above the treetops), secondly, the species that hunt at edge structures, and thirdly, the specialists for foraging in narrow spaces, for example forest specialists below the canopy such as the bats of the genera mouse-eared bats (Myotis) or long-eared bats (Plecotus). “These forest specialists were significantly less active close to wind turbines, especially near turbines with large rotors, and during midsummer months,” says Voigt. Starting from a distance of 450 meters towards wind turbines, the activity of these bats dropped by almost 50 percent close to the turbines.
Wind turbines at forest sites thus not only pose a direct threat to those bats that hunt for insects above the treetops but also deteriorate the habitat for bats that live below the treetops in the forests and hunt for insects there. “Even though forest specialists are not at risk of colliding with turbines, they are nonetheless suffering from wind turbines in forests due to habitat loss as they avoid operating wind turbines over a distance of several hundred meters,” concludes Voigt.
The authors therefore recommend that wind turbines should not be sited inside forests but in the open landscape and in particular, that near-natural forests with a varied vegetation structure should be avoided. If wind turbines nevertheless have to be erected in forests, compensatory measures are essential. A pivotal component of these mandated compensatory measures should be to set aside an appropriately large area of forest as a wilderness area for forest specialist bats, so that the loss of habitat caused by the operation of the turbines is compensated for.
Upcycling Compact Discs for Flexible and Stretchable Bioelectronic Applications
by Matthew S. Brown, Louis Somma, Melissa Mendoza, Yeonsik Noh, Gretchen J. Mahler, Ahyeon Koh in Nature Communications
New research from Binghamton University, State University of New York offers a second life for CDs: Turn them into flexible biosensors that are inexpensive and easy to manufacture.
In a paper, Matthew Brown, PhD ’22, and Assistant Professor Ahyeon Koh from the Department of Biomedical Engineering show how a gold CD’s thin metallic layer can be separated from the rigid plastic and fashioned into sensors to monitor electrical activity in human hearts and muscles as well as lactate, glucose, pH and oxygen levels. The sensors can communicate with a smartphone via Bluetooth.
The fabrication is completed in 20 to 30 minutes without releasing toxic chemicals or needing expensive equipment, and it costs about $1.50 per device. According to the paper, “this sustainable approach for upcycling electronic waste provides an advantageous research-based waste stream that does not require cutting-edge microfabrication facilities, expensive materials or high-caliber engineering skills.” Also contributing to the research are BME Professor Gretchen Mahler; Melissa Mendoza, PhD ’22; and Louis Somma, MS ’22, as well as Assistant Professor Yeonsik Noh from the University of Massachusetts — Amherst. Koh said she first considered the idea of converting the CDs into sensors while doing postdoctoral research at the University of Illinois.
“I had an idea: Maybe we could harvest the critical material from the CD and then upcycle to sensing systems,” she said. “I talked to Matt about my idea during the early stage of his dissertation research, and he wanted to continue this research.”
Brown investigated previous research on biosensors made from CDs, but he found that those sensors retained a rigid structure and had a more limited number of applications than he and Koh hoped to achieve. The first step is removing the metallic coating from the plastic beneath using a chemical process and adhesive tape.
“When you pick up your hair on your clothes with sticky tape, that is essentially the same mechanism,” Koh said. “We loosen the layer of metals from the CD and then pick up that metal layer with tape, so we just peel it off. That thin layer is then processed and flexible.”
To create the sensors, Binghamton researchers used a Cricut cutter, an off-the-shelf machine for crafters that generally cuts designs from materials like paper, vinyl, card stock and iron-on transfers. The flexible circuits then would be removed and stuck onto a person. With the help of a smartphone app, medical professionals or patients could get readings and track progress over time.
As Brown’s PhD advisor, Koh is thrilled to see something she speculated could be possible almost a decade ago is now a reality.
“I was so lucky to have Matt in the lab, because otherwise it would have stayed an idea from my postdoc research,” she said. “Some of my postdoc colleagues remember me talking about this idea to them, and they’re so excited about it.”
Brown is headed to San Diego to work for Dexcom, which makes continuous glucose monitors, but he has ideas about how the CD-to-sensor technology could be improved: “We used gold CDs, and we want to explore silver-based CDs, which I believe are more common. How can we upcycle those types of CDs with the same kind of process? We also want to look at if we can utilize laser engraving rather than using the fabric-based cutter to improve the upcycling speed even further.”
Like her former student, Koh would like to expand the CD-to-sensor research as well, possibly with the help of the campus community.
“Maybe we can create a box on campus where we could collect CDs,” she said. “We also could have more generalized step-by-step instructions on how to make them in a day, without any engineering skills. Everybody can create those kinds of sensors for their users. We want these to become more accessible and affordable, and more easily distributed to the public.”
Plastic pollution fosters more microbial growth in lakes than natural organic matter
by Sheridan, E.A., Fonvielle, J.A., Cottingham, S. et al. in Nature Communications
A study of 29 European lakes has found that some naturally-occurring lake bacteria grow faster and more efficiently on the remains of plastic bags than on natural matter like leaves and twigs.
The bacteria break down the carbon compounds in plastic to use as food for their growth. The scientists say that enriching waters with particular species of bacteria could be a natural way to remove plastic pollution from the environment. The effect is pronounced: the rate of bacterial growth more than doubled when plastic pollution raised the overall carbon level in lake water by just 4%. The results suggest that the plastic pollution in lakes is ‘priming’ the bacteria for rapid growth — the bacteria are not only breaking down the plastic but are then more able to break down other natural carbon compounds in the lake.
Lake bacteria were found to favour plastic-derived carbon compounds over natural ones. The researchers think this is because the carbon compounds from plastics are easier for the bacteria to break down and use as food. The scientists caution that this does not condone ongoing plastic pollution. Some of the compounds within plastics can have toxic effects on the environment, particularly at high concentrations.
“It’s almost like the plastic pollution is getting the bacteria’s appetite going. The bacteria use the plastic as food first, because it’s easy to break down, and then they’re more able to break down some of the more difficult food — the natural organic matter in the lake,” said Dr Andrew Tanentzap in the University of Cambridge’s Department of Plant Sciences, senior author of the paper.
He added: “This suggests that plastic pollution is stimulating the whole food web in lakes, because more bacteria means more food for the bigger organisms like ducks and fish.”
The effect varied depending on the diversity of bacterial species present in the lake water — lakes with more different species were better at breaking down plastic pollution.
A study published by the authors last year found that European lakes are potential hotspots of microplastic pollution. When plastics break down they release simple carbon compounds. The researchers found that these are chemically distinct to the carbon compounds released as organic matter like leaves and twigs break down. The carbon compounds from plastics were shown to be derived from additives unique to plastic products, including adhesives and softeners. The new study also found that bacteria removed more plastic pollution in lakes that had fewer unique natural carbon compounds. This is because the bacteria in the lake water had fewer other food sources. The results will help to prioritise lakes where pollution control is most urgent. If a lake has a lot of plastic pollution, but low bacterial diversity and a lot of different natural organic compounds, then its ecosystem will be more vulnerable to damage.
“Unfortunately, plastics will pollute our environment for decades. On the positive side, our study helps to identify microbes that could be harnessed to help break down plastic waste and better manage environmental pollution,” said Professor David Aldridge in the University of Cambridge’s Department of Zoology, who was involved in the study.
The study involved sampling 29 lakes across Scandinavia between August and September 2019. To assess a range of conditions, these lakes differed in latitude, depth, area, average surface temperature and diversity of dissolved carbon-based molecules. The scientists cut up plastic bags from four major UK shopping chains, and shook these in water until their carbon compounds were released. At each lake, glass bottles were filled with lake water. A small amount of the ‘plastic water’ was added to half of these, to represent the amount of carbon leached from plastics into the environment, and the same amount of distilled water was added to the others. After 72 hours in the dark, bacterial activity was measured in each of the bottles.
The study measured bacterial growth — by increase in mass, and the efficiency of bacterial growth — by the amount of carbon-dioxide released in the process of growing. In the water with plastic-derived carbon compounds, the bacteria had doubled in mass very efficiently. Around 50% of this carbon was incorporated into the bacteria in 72 hours.
“Our study shows that when carrier bags enter lakes and rivers they can have dramatic and unexpected impacts on the entire ecosystem. Hopefully our results will encourage people to be even more careful about how they dispose of plastic waste,” said Eleanor Sheridan in the University of Cambridge’s Department of Plant Sciences, first author of the study who undertook the work as part of a final-year undergraduate project.
Reaction of Sulfur and Sustainable Algae Oil for Polymer Synthesis and Enrichment of Saturated Triglycerides
by Adarsha Gupta, Max J. H. Worthington, Harshal D. Patel, Martin R. Johnston, Munish Puri, Justin M. Chalker in ACS Sustainable Chemistry & Engineering
To save the world’s fish stocks and oceans, scientists are racing to find better and sustainable ways to make healthy nutritional products such as Omega-3 fatty acids, biodiesel, aquaculture and livestock food from fast-growing microalgae.
New research at Flinders University has discovered a simple, low-cost and effective way to extract high-value bioactives from single-cell algae oil — using waste sulfur from industries such as petrochemical production. The innovative algae oil production process outlines the new method of using waste sulfur to produce enriched saturated triglycerides from sustainably produced algae oil. The process uses a single reaction to simultaneously produce valuable polymers from polyunsaturated triglycerides and enrich saturated triglycerides for various value-added applications. The sulfur reaction can draw up to 90% of the unsaturated triglycerides from cultured single-cell algae.
“In this study, we build upon our body of work in sulfur chemistry to find an innovative way to process triglycerides from lipid-rich microalgae,” says Professor Justin Chalker, whose organic polymers have been adapted for environmental remediation, slow-release fertiliser, insulation and e-waste.
“In this case, the algae oil is reacted with sulfur. The polyunsaturated triglycerides form polymers with many established uses, such as environmental remediation. The saturated triglycerides remain unreacted in this process, for recovery and ultimate conversion to value-added substances such as biodiesel,” says Professor Chalker.
Associate Professor Munish Puri, from Flinders University’s Bioprocessing Lab in Medical Biotechnology, has been working on single-cell oils to produce new materials suitable for nutritional supplements, animal-free meats, biodiesel and other products.
“There is growing interest in the bio-based production of lipids from algae,” says Professor Puri, who has a background in industrial biotechnology and is leading the precision fermentation platform for producing such oils. “Single-cell thraustochytrids are especially attractive in this regard, as they can produce over 50% of their weight as triglycerides.
“But despite their promise, there remains a need for versatile downstream processing to enrich these so-called ‘single-cell oils’ into fatty acid classes based on degree of unsaturation. And that’s what this novel approach is helping to address.”
Relic Groundwater and Prolonged Drought Confound Interpretations of Water Sustainability and Lithium Extraction in Arid Lands
by Brendan J. Moran, David F. Boutt, Sarah V. McKnight, Jordan Jenckes, Lee Ann Munk, Daniel Corkran, Alexander Kirshen in Earth’s Future
A groundbreaking new study led by researchers at the University of Massachusetts Amherst in collaboration with the University of Alaska Anchorage, is the first to comprehensively account for the hydrological impact of lithium mining. Since lithium is the key component of the lithium-ion batteries that are crucial for the transition away from fossil fuels and towards green energy, it is critical to fully understand how to responsibly obtain the precious element.
Previous studies have not addressed two of the most important factors in determining whether lithium is obtained responsibly: the age and source of the water the lithium is found in. This first-of-its-kind study is the result of more than a decade of research, and it suggests that total water usage in the Salar de Atacama is exceeding its resupply — though, as the team also points out, the impact of lithium mining itself is comparatively small. Lithium mining accounts for less than 10% of freshwater usage and its brine extraction does not correlate with changes in either surface-water features or basin-water storage.
Lithium, says David Boutt, professor of geosciences at UMass Amherst and one of the paper’s co-authors, is a strange element. It’s the lightest of the metals, but it doesn’t like to be in a solid form. Lithium tends to occur in layers of volcanic ash, but it reacts quickly with water. When rain or snowmelt moves through the ash layers, lithium leaches into the groundwater, moving downhill until it settles in a flat basin where it remains in solution as a briny mix of water and lithium. Because this brine is very dense, it often settles beneath pockets of fresh surface water, which float on top of the lithium-rich fluid below. These fresh-water lagoons often become havens for unique and fragile ecosystems and iconic species such as flamingos.
More than 40 percent of the world’s proven lithium deposits are located in the Salar de Atacama, a massive, arid Chilean salt flat encompassing approximately 850 square miles, and the site of the research. The Salar de Atacama is host to a number of ecologically unique wildlife preserves and is also the ancestral home of several Atacameño indigenous communities, with whom the UMass team worked. Because the salt flats are so ecologically sensitive and depend on scarce supplies of fresh water, the use of water in the Salar de Atacama runs the risk of disturbing both the ecological health of the region and the indigenous ways of life. And yet, up until now, there has been no comprehensive approach to gauging water use or lithium mining’s impact in the Salar de Atacama.
“To understand the environmental effect of lithium mining,” says Brendan Moran, a postdoctoral research associate in geosciences at UMass Amherst and the lead author of the paper, “we need to understand the hydrology in the region the lithium is found. That hydrology is much more complex than previous researchers have given it credit for.”
To illustrate the complexity, and the previous misconception about the Salar de Atacama’s hydrology, Moran and Boutt draw on the metaphor of a bank account. Imagine that you get a paycheck every month; when you go to balance your checkbook, as long as your monthly expenditures don’t exceed your monthly income, you are financially sustainable. Previous studies of the Salar de Atacama have assumed that the infrequent rainfall and seasonal runoff from the mountain ranges that ring it were solely responsible for the water levels in the salt flats, but it turns out that assumption is incorrect.
Using a variety of water tracers that can track the path that water takes on its way to the Salar de Atacama as well as the average age of water within different water bodies, including surface waters and sub-surface aquifers, Moran and his colleagues discovered that though localized, recent rainfall is critically important, more than half of the freshwater feeding the wetlands and lagoons is at least 60 years old. “Because these regions are so dry, and the groundwater so old,” says Moran, “the overall hydrological system responds very slowly to changes in climate, hydrology and water usage.” At the same time, short-term climate changes, such as the recent major drought and extreme precipitation events, can cause substantial and rapid changes to the surface water and the fragile habitats they sustain. Given that climate change is likely to cause more severe droughts over the region, it could further stress the area’s water budget.
To return to the accounting metaphor, the paycheck is likely getting smaller and isn’t coming monthly, but over a period of at least 60 years, which means that researchers need to be monitoring water usage on a much longer time scale than they currently do, while also paying attention to major events, like droughts, in the region. Complete hydrological monitoring requires additional tools paired with these geochemical tracers. The UMass and UAA teams used water usage data from the Chilean government, and satellite imagery, which allowed them to assess the changing extent of wetlands over the past 40 years, rain gauges, and satellite measurements to determine changes in precipitation over the same period.
Given how long it takes for groundwater to move within the basin, “The effects of water over-use may still be making their way through the system and need to be closely monitored,” says Moran, “potential impacts could last decades into the future.”
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